This project undertakes an analysis of the mechanisms of transformation and gene regulation by human adenoviruses. Deletion mutants of adenovirus type 2 (Ad 2), isolated from laboratory stocks, or constructed in vitro, will be used to identify regions of the viral genome involved in transformation or the regulation of gene expression. The phenotypes of mutants with apparent defects in transformation or regulation will be carefully studied to determine how the deleted regions of the genome are involved in those processes.